Mouse serum as a medium supplement for murine immune responses in vitro

In vitro generation of secondary anti-viral H-2 restricted cytotoxic T cells (Tc cells) alloreactive Tc cells, alloantigen-induced T cell proliferation, bacterial lipopolysaccharide (LPS)-induced B cell proliferation and anti-dinitrophenyl IgM and IgG antibody responses were used to evaluate pools of mouse sera (MS) and other animal sera as medium supplements by comparison with 5-10% fetal calf serum (FCS). Some batches of normal MS were comparable with FCS while others inhibited Tc cell responses when used at 1%, particularly with limiting stimulator cell numbers. In contrast, 2 pools of nude mouse sera and several pools of MS from thioglycollate-injected mice (TMS) used at 1% were consistently comparable with FCS at 5-10% in terms of in vitro generation of effector Tc cells and antibody secreting B cells. TMS at 1% was satisfactory for Tc cell responses either fresh, after heat inactivation at 56 degrees C for 30 min, or after storage for 6 months at -70 degrees C. 0.5% or 2% heat-inactivated rat and rabbit sera (but not guinea pig sera) were also satisfactory for Tc cell generation. Total thymidine incorporation into proliferating B or T cells was 5-15-fold lower in cultures with 1% normal MS, nude MS or TMS than with 5% FCS, but stimulation indices with 1% nude MS and TMS were similar to those with 5% FCS, whereas 1% normal MS apparently completely inhibited stimulation. One percent syngeneic TMS is a convenient, reliable alternative to 5-10% FCS in culture medium, supporting all the murine responses listed above.